SEATTLE (AP) -- Tens of thousands across the country peacefully chanted, picketed and protested Monday against President Donald Trump's immigration and labor policies on May Day, despite a small pocket of violent unrest in the Pacific Northwest.

Peaceful protesters flocked to the streets in Chicago. At the White House gates, they demanded "Donald Trump has got to go!"

But police shut down a protest in Portland, Oregon, that they said had become a riot, after marchers began throwing smoke bombs and other items at officers. Police said they made more than two dozen arrests as a group of anarchists wearing black bandanas and ski masks grew unruly, reportedly breaking windows at businesses, setting fires on downtown streets and damaging a police car.

Five people in Seattle were arrested, one for hurling a rock as pro- and anti-Trump demonstrators faced off.

In the Washington state capital of Olympia, police ordered protesters to disperse, calling them "members of a mob" as some threw bottles, used pepper spray and fired marbles from slingshots at officers. Objects struck nine officers and nine people were arrested, according to Olympia Police Chief Ronnie Roberts.

In Oakland, California, at least four were arrested after creating a human chain to block a county building where demonstrators demanded that county law enforcement refuse to collaborate with federal immigration agents.

Despite the West Coast clashes, most nationwide protests were peaceful as immigrants, union members and their allies staged a series of strikes, boycotts and marches to highlight the contributions of immigrants in the United States.